'Good strategy'

What particularly annoys the union is the suggestion that the marathon negotiations have not been held in good faith.

Mr Randoph's email says the company had "a good strategy" when it went into this "fight" and that strong leadership will make it "a winnable" fight.

Mr Maher believes BHP is fighting to retain conditions it gained under the WorkChoices policies of the Howard government.

"I don't know why they've had us around the table for the last 15 months if [it's] never been negotiable; that's not bargaining in good faith. No wonder the workforce is upset with them," he said.

"The company has painted itself into a corner with this managerial prerogative stuff. If they want WorkChoices back, they should come out and say so and they'll have an opportunity to publicly argue that."

The unions reject BHP's claim that they are trying to extend their power.

"There are a number of claims there that are permissible even under WorkChoices - putting superannuation up from 9 per cent to 12 per cent.

"They pay their staff 12 per cent super contributions, they can pay the workers who produce the goods the same amount of super; that's a straightforward pay claim.

"The claim that contractors be paid the same wages for doing the same work is a money claim; they willingly agreed to that for decades and then under WorkChoices it couldn't be agreed and they immediately cut the wages of the contractors workforce, some by half.

"So it's a rip-off of workers which is at the core of why people are angry with the company. And if they can't see that, if they think that that's really a line-in-the-sand managerial prerogative thing, they're deluding themselves."

Another indication of BHP's hard line was its recent suggestion that it might close down one of its older open-cut mines if the industrial action continued.

However industry analysts have dismissed that as unlikely due to the quality of its coking coal, said to be among the best in the world.